Cellular broadband systems, such as Long Term Evolution (LTE) systems, deliver higher mobile download speeds and thereby allow for increased data usage on mobile devices, such as laptops, smart phones, and tablets. Although network operators are attempting to address the challenge of increased data usage by upgrading cellular Wide Area Networks (WANs), in some cases, network upgrades may not be adequate. An increasing number of mobile devices have local area network (LAN) capabilities, wherein data originally targeted for cellular networks may be delivered via, for example, wireless-fidelity (Wi-Fi) or femtocell networks. The handover of data originally targeted for cellular networks to, for example, a Wi-Fi network is referred to herein as “Wi-Fi offload”.
Depending on the mobile device and/or cellular network involved in the Wi-Fi offload, when the mobile device connects to the Wi-Fi network, a new IP address is assigned to the mobile device by the Wi-Fi network. Thereafter, all new communications directed to the mobile device can use the new IP address. Although established connections can still continue over the cellular network, some mobile devices and/or cellular networks may be configured to disable the cellular network connections when the mobile device establishes connection with the Wi-Fi network. The previously established connection with the cellular network is thereafter reestablished over Wi-Fi, using the new IP address. This broken connection may result in service interruption and degrade the user experience. In addition, traffic sent via Wi-Fi may be sent over the Internet, which provides for only best-effort delivery but does not provide any guarantees that data is delivered or that a user is given a guaranteed quality of service (QoS) level or a certain priority. Unlike the Internet which provides for only best-effort delivery, the LTE core network provides QoS, i.e., the ability to provide different priorities to different applications, users, or data flows, or to guarantee a certain level of performance to a data flow, so that real time traffic, like voice calls, will have better performance.
In order to maintain the data connection during Wi-Fi offload, the network operator may use a virtual private network (VPN). A VPN extends resources used on a private network across public networks like the Internet. The VPN enables host devices to establish virtual point-to-point connections through the use of dedicated connections and/or encryption, and to send and receive data across public networks as if it were a private network with all the functionality, security and management policies of the private network. However, using a VPN to maintain the data connection during Wi-Fi offload increases the cost of operating the cellular network and does not provide for controlling quality of service.
FIG. 1 is a block diagram of an LTE system that may be used during Wi-Fi offload. The LTE system includes, among other components, a core network 104 and one or more evolved Node Bs (eNBs) 102 (that is, eNBs 102a, 102b, and 102c). The core network 104 includes a serving gateway 114 and a mobility management entity (MME) 116. Serving gateway 114 routes incoming and outgoing internet protocol (IP) packets and handles handover between eNBs 102 and MME 116 handles signaling related to mobility and security. Each eNB 102 functions as a base station for the LTE system and includes an LTE radio 112 (that is, LTE radios 112a, 112b, and 112c) for forwarding user data and signaling between core network 104 and user equipment (UE) 106 operating on the LTE system. Application servers 121 may be directly link to the core network 104 to enhance quality of service for certain types of applications, such as telephony. Other application servers 120 may also be linked to core network 104 through the Internet 130.
UE 106 includes a connection manager 107 that determines where to route data from the various applications. For example, connection manager 107 may route data through the LTE system via an LTE modem 108 of user equipment 106 or through a Wi-Fi interface via a Wi-Fi modem 109 of the user equipment. If user equipment 106 is performing Wi-Fi offload, data is routed from user equipment 106 via Wi-Fi modem 109 to a Wi-Fi access point (AP) 110 which is connected to the Internet 130 outside of the cell system. This may cause a change in the IP address and/or may cause loss of QoS control and may affect the performance of some applications. Packets sent during Wi-Fi offload over the Internet 130 using “best effort” delivery may be adequate for some applications, such as file downloads or financial transactions, but may not be acceptable for some services, such as real time voice and video services. Therefore, cellular operators that provide Wi-Fi offload capability in user equipment 106 typically may not offload telephone calls, but rather keep them on core network 104 to control QoS, while offloading other data services to Wi-Fi, thereby limiting the amount of data offloaded to the Wi-Fi network.
Two broadband systems may occupy adjacent spectrum such as occurs in the upper 700 MHz band in the United States of America. This may result in interference in locations covered by a first broadband system that are near locations covered by a second broadband system. For example, undesired, adjacent channel signals with high strength from the second broad band system may cause interference in locations covered by the first broadband system. In addition, there may also be interference in the first broadband system based on the strength of a desired signal in first broadband system. For example, if the strength of the desired signal from the first broadband system is weak in locations covered by the first broadband system that are farther away from the LTE cell site, these locations may have larger areas of interference than locations that are closer to the LTE cell site. Therefore, a mobile device in a location with interference from, for example, a weak or undesired signal may be configured to offload to a Wi-Fi network.
Accordingly, there is a need for an improved method and apparatus for offloading broadband traffic from a cellular wide area network to a Wi-Fi network and for reducing load on the cellular wide area network and/or mitigating interference, without interrupting service or reducing quality of service for certain types of traffic.
Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help to improve understanding of embodiments of the present invention.
The apparatus and method components have been represented where appropriate by conventional symbols in the drawings, showing only those specific details that are pertinent to understanding the embodiments of the present invention so as not to obscure the disclosure with details that will be readily apparent to those of ordinary skill in the art having the benefit of the description herein.